As electronic equipment, have become more complicated, it has been necessary to provide units to facilitate, or in some cases make possible, the servicing of such electronic equipment to keep the same in good operational condition. This has been particularly true of electronic equipment used to receive T.V. signals, including the now common T.V. receiver and closed-circuit T.V. monitor, and the need for such service equipment has become even more acute with the increased use of color T.V. receivers and monitors.
Servicing of television receivers and closed-circuit T.V. monitors, and particularly color television receivers, often requires the use of special signal generating apparatus for producing stable test patterns such as a plurality of color bars each of different hue, a crosshatch pattern of white vertical and horizontal lines, or an orderly array of white dots to be displayed on the image-producing device of the T.V. receiver or closed-circuit monitor.
These patterns are useful for checking and correctly adjusting linearity and pincushion distortions in scanning circuits, for checking and correctly adjusting operation of electron beam convergence, and for checking and adjusting color phasing and matrixing circuits in color television receivers.
While the need for more complex servicing equipment exists in view of the more complicated electronic equipment to be serviced, there obviously also exists a need to minimize such complexity to the extent possible in view of the seemingly ever increasing needed functions. To this end, it is desirable that servicing equipment be, and be maintained, lightweight, portable, reliable, versatile, and yet capable of simple operation.
Servicing equipment for T.V. receivers have been heretofore suggested and/or utilized. Included among such known equipment is equipment generally directed to producing test patterns for servicing T.V. receivers, and some said suggested equipment has included such features as digital circuitry, color bar pattern generation, and dot and crosshatch generation, as well as various frequency divider systems. Among patents showing one or mre of these features are U.S. Pat. Nos. 3,019,289; 3,529,079; 3,250,853; 3,188,383; 2,836,717; 3,493,673; 3,430,067; 2,975,229; 3,634,612; 2,943,144; 3,586,755; 3,334,178; 2,824,225; and 2,683,187.
Such servicing equipment now suggested and/or utilized has not, however, proved to be completely successful at least in accomplishing all of many and diverse desired ends. For example, known servicing equipment, while providing test patterns, has not provided fully satisfactory patterns and/or has not produced the number of various patterns that might be needed. In accordance, known servicing equipment has not fully provided needed simplicity, versatility and/or reliability, and circuitry problems related to such equipments have not been eliminated or satisfactorily reduced in many instances.
Thus, even though much servicing equipment has been heretofore suggested and/or utilized, a need still existed for a system that could eliminate, or at leat substantially reduce, many of the problems in equipment of this type.
In my above-referenced copending U.S. Pat. Application Ser. No. 677,196, I have described and claimed an improved system and method for generating test signals for servicing a T.V. receiver and the like which has the capability of producing a number of test patterns that were unobtainable prior to my invention. This invention expands upon my previous invention and provides a further improvement in the system and method as well as providing more test patterns that have been heretofore not available and yet are useful in servicing of T.V. receivers and the like.